Dover Municipal Well 4

Overview

Dover Municipal Well 4 is a Superfund site in Dover, New Jersey, added to the National Priorities List in September 1983. The site centers on a municipal drinking water well that served about 22,000 people before being shut down in 1980. Sampling had revealed chlorinated volatile organic compounds in the groundwater, traced back to a dry cleaner on Route 46. The town replaced the well with a standby well, and EPA took over cleanup planning.

EPA identified 24 contaminants of concern at the site. The main ones are volatile organic compounds, including tetrachloroethene (also called perchloroethylene or PCE), trichloroethene (TCE), vinyl chloride, benzene, toluene, and related chlorinated solvents. Heavy metals such as arsenic, lead, and mercury, along with phthalates, are also present. Most contaminants were found in groundwater. Several, including PCE, TCE, vinyl chloride, and cis-1,2-dichloroethene, are also present in soil near the former dry cleaner source area.

EPA divided the site into two operable units. The first addresses groundwater and uses air stripping, contaminated water extraction, treated water reinjection, and ongoing monitoring. The second targets the contamination source. Under the 2005 cleanup plan, EPA demolished the dry cleaner and three nearby homes, excavated contaminated soil, and applied chemical oxidation treatments in 2010, 2011, 2012, and 2014 to break down remaining contaminants. Construction was completed in September 2010. In early 2024, EPA removed additional soil with high contamination levels near a former waste pit, finishing that work within about three months. Contamination levels have dropped and continue to decrease through natural processes.

The site reached sitewide ready for anticipated reuse status in June 2024, meaning cleanup goals have been met with no unacceptable risks under current and expected future land uses. Human exposure is under control and groundwater migration is stabilized with no unacceptable discharge to surface water. EPA completed its most recent five-year review on February 28, 2025. Groundwater is still sampled twice a year, in spring and fall, to track contamination levels. Institutional controls remain in place, restricting groundwater use, prohibiting new drinking water wells, and limiting land uses that are not compatible with the cleanup level achieved.

Community members can get involved through EPA's Community Involvement Program. Site records are available at the EPA Administrative Record File Room at 290 Broadway, 18th Floor, New York, and at the Dover Free Public Library at 32 East Clinton Street in Dover, New Jersey. Joel Waddell is the Community Involvement Coordinator and Diego Garcia is the Remedial Project Manager for the site.